Mysterious onset of sinus tachycardia

In January of this year I had a sudden onset of sinus tachycardia. I'm 28 years old, female, healthy and get plenty of exercise. I had just got home from walking my dog, it was a short walk around the block as the weather was bad, I hadn't been running or doing anything strenuous and I was just about to sit down with a cup of tea and watch the tv when all of a sudden my heart started beating extremely fast. This has never happened to me before. I tried taking long deep breaths to try and slow my heart but nothing was working so I called for an ambulance. My heart was beating about 200bpm and once the paramedic arrived he hooked me up to a monitor and it was beating 160bpm. From the read out on the monitor he saw that there were no blockages or skipped/irregular beats but my heart just seemed to be beating really fast. I've suffered with anxiety in the past and had a couple of anxiety attacks but this was not anxiety! The paramedic took me to hospital where I had every test you could possibly think of and nothing abnormal was found. I had a slightly raised d-dimer which made them think it may be caused by a blood clot or infection but again nothing was found. No one in the hospital could explain to me what had happened, why and if it would ever happen again. This experience was very frightening and Im wondering if anyone has ever experienced the same or similar or if you know what it is that caused it?
My mum, who is a medical professional, thinks it was a sudden rush of hormones as it happened the day before I started my period. Could she be right??
Please help.

It's very uncommon for sinus tachycardia to suddenly peak at 200 bpm unless you are having a panic attack and/or you are working out at peak intensity. If you did experience an event of rapid heart rate that came out of nowhere, it's more likely to be an event of atrial tachycardia (supraventricular tachycardia). Sinus tachycardia usually have an obvious cause (anxiety, heavy bleeding, infections, etc.). Of course, your heart rate can be elevated without an obvious cause, but not as high as 200 bpm.

I've had runs of sinus tachycardia caused by low blood pressure or low blood sugar and stress, but usually it peaks at 120-130 bpm. That said, supraventricular tachycardias are almost always benign and nothing to worry about, especially if your heart is healthy.

Sounds like SVT or PSVT which many of us have on here, myself included (I have PAC and PVC also) and it's all benign in a healthy heart. Have you gone to see a cardio? They may want to put you on a monitor so you can be properly diagnosed.

I went to the doctors for a follow up after I left hospital thinking they might put me on a monitor and the guy I saw wouldnt even let me speak. He kept interrupting me and tried to convince me it was anxiety and gave me a load of beta blockers. He was useless and kind of put me off going back.
It hasnt happened since but it still plays on my mind. It was very scary!

Without the start of it being captured on a monitor you can't say for sure but it sounds like accessory pathway svt. Essentially an extra muscle fiber in the heart causing the heart beat to get caught in a circle. The biggest tell tail sign is that it starts and stops in one beat. If yours ramped up or down then it could be an anxiety attack from adrenaline or too much caffeine or being a bit dehydrated. The problem is that it may be very hard to catch especially if this is your first ever episode. I had accessory pathway svt my whole life but when I was young it was very rare. It wasn't until I reached my 30s that it started to become more frequent and it wasn't until my 40s when it started to disrupt my life. The thing is you have to be kind of frequent for them to be able to ablate and correct the issue because they need to cause an episode to happen and that can be hard to do if the episodes are rare. So until you are able to get this diagnosed I would suggest trying to bear down and hold your breath like going to the bathroom to see if that will get it to stop or even drinking a very cold glass of water.

As the other posters have stated, atrial issues are not a danger to you so rest assured you will be just fine and really only inconvenienced when it happens if it continues to happen. I would say try to not worry about it too much at this point and just keep an eye on things. You can try and find a new doctor at this point but it may be too early for you to really get on top o it so if you can't get it captured if you happen to get an episode and can't get it to stop in a fair amount of time then head to the er to get some help but in general unless the tachycardia sustains for a very long extended amount of time you are not in danger. And then at some point if it begins to look like it is happening more often then find a doctor who will take you seriously. But try not to worry. I lived with it my whole life and I am just fine. Take care and keep us posted on how you are doing.

Helen, I'm sorry but I totally missed this post. I agree with the posters above. It's very difficult to get sinus rate to 200 without heavy physical output. It's very possible that you had an episode of perhaps SVT. These are for the most part troublesome but not dangerous. The best thing to do is to put you on a long term monitor with hopes of catching one. 30 day monitors are easily worn with two electrodes that are replaced daily.

Regarding your beta blocker. Taking it when you feel that you need it is not the way that it should be taken. This advice is directly from my electrophysiologist. You're supposed to have a therapeutic level in your blood at all times for it to work properly. Depending on the beta blocker, it could have a very short half life, possibly 5 hours or less. This means that as soon as you take it, your body begins to eat away at it so after only 5 hours it has been reduced to half it's strength. so as you can see, it's good to take this continually.

I could have wrote this myself. I'm having the exact same problem. It all started a day before my period, just like you! I'm still having palpitations and an increased sensitivity to my heart beat. I see a cardiologist next week. Did you ever find the cause? Or did you receive successful treatment?

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